Sanding mechanism



MAIN PES- 3 Nova 26, 19

. C. A. CAMPBELL SANDING MECHANI SM Filed April 8, 1959 2 Sheets-Sheet 1 T/MIZVG E55.

Zmventor attorneys Nov. 26, 1940. C CAMPBELL 2,222,604

SANDING MECHANISM Filed April 8, 1959 2 Sheets-Sheet 2 (IttornegS Patented Nov. 26, 1940 I UNITED STATES PATENT OFFICE to The New York Air poration of New Jersey Brake Company, a cor- Application April 8, 1939, Serial N 0. 266,819

Claims.

This invention relates to control mechanism for sanders.

While the invention is generally applicable in whole or in part to railway brakes of the type long standard on American railroads, it derives its greatest utility in connection with high speed brakes such as Schedule H80 and Schedule AHSC, in which the speed of propagation of braking action is very high and in which the braking ratios are so high-at least in emergency applications-as to render wheel sliding probable unless the condition of the rails is good. With such a system it is considered important to sand at least as early as the commencement of any emergency application and preferably slightly in advance of the commencement of such an application.

In a prior Patent No. 2,035,533, issued Marchv 31, 1936, there is described and claimed a sander control valve which may be manually operated to sand in either of two ways: (1) sanding at will, which continues only so long as a particular sanding at will button is held depressed, and (2) timed sanding which, when initiated by depressing a distinct ftimed-sanding button, or by the occurrence of an emergency application, will continue for a definite time interval. This time interval is determined on the basis of the time required for an emergency stop, the purpose being to cause sanding to continue at leastuntil the train is brought to rest. 1

Experience gained by observing the sander valve of the prior Campbell patent in actual commercial use, suggests the desirability of certain additional functions, some of which are secured by changing the porting of the sander valve and others of which are gained by the use of accessory apparatus, preferably electrical.

As used in actual service, sanding at will is used almost exclusively in starting. Automatic timed sanding is used for emergency applications and is a necessary incident thereto. For service braking the tendency is to use manually initiated timed sanding, but since the time period is long, some reset means is needed to avoid waste of sand.

The present invention gives the sanding at will button the additional function of a reset button for terminating timed sanding.

Since sanding at will is used only in starting, means are provided to limit such sanding to propelling units. This saves sand and avoids resistance to rolling of the wheels such as is caused by sanding throughout the train.

With the improved device, timed sanding always occurs ahead of all braked wheels. If the engineer thinks sanding for a service application is needed, he simply strikes the timed sanding button and then shifts his brake valve to service. When he Wishes sanding to end short of 5 the full timed period he presses the sanding at will button and the sander valve resets.

Thus the device has a number of important operative characteristics, the three most important being (1) ability to sand at will in starting, such sanding occurring in front of the propelling wheels only; (2), ability to initiate timed sanding throughout the train manually and to terminate it at any time prior to its automatic termination, and (3) automatic timed sanding throughout the train upon the occurrence of an emergency application. This inhibits resetting of the sander valve while the emergency valve is active.

The preferred embodiment of the invention will now be described in connection with the accompanying drawings, in which-- Figure 1 is a diagrammatic View showing the sanding control valve with its fiuid pressure connections and controlling switches interposed in the electric sander control circuits.

Figure 2 is a diagram of one magnet valve connected to control a local sander valve, the magnet valve being interposed in one of the circuits shown in diagram in Figure 1.

Figures 3, 4 and 5 are axial sections through thesanding control valve drawn on an enlarged scale as compared to Figure 1, Figure 3 showing the normal or running position of Figure 1; Figure 4 showing the device in the position which it assumes during timed'sanding, and Figure 5 showing the position assumed upon shift to terminate timed sanding, as the result of the operation of the sanding at will button.

Before describing the sanding valve, it should be understood that on a high speed train all wheels are braked. It is considered advisable to apply a sander to every set of braked wheels.

Some high speed trains are articulated in whole, some are articulated in part, and some are composed of independent units. This affects the number of trucks per unit with a consequent effect on the specific location of the sanders, but so far as the present invention is concerned, it suifices to say that the sanders are located in advance of every set of braked wheels, or at least in front of every truck, and are controlled in two semi-independent groups by electric means. One group comprises sanders for the propelling wheels, and the other group sanders for other braked wheels.

Mounted at the head of the train is a source of electric current indicated as a battery 6. Extending throughout the length of the train is a common return wire 'I which is connected to one terminal of the battery 6 and which is connected from car to car by separable connectors, diagrammatically illustrated at 8.

Also extending throughout the length of the train is the trailer sanding line 9 connected from car to car by separable connectors 8. The two leading units A and B are assumed to be propelling units, and the next two units C and D are trailer units and have no propelling equipment. Only two trailers are shown in the drawings, but any number may be used in practice.

The drive wheel sanding line II leads through the propelling units A and B only and is connected between these units by separable conneotors 8.

Connected between the lines I and 9 on the trailing units only are the windings I2 of sanding magnet valves. One magnet valve per trailer is indicated, but the number is immaterial. It is usually practicable to handle all the sanders on one vehicle by one magnet valve. If, for any reason, a larger number is desirable, simple duplication is all that is involved.

The same comment applies to the propelling units on each of which is shown a single winding I3 for a corresponding magnet valve. The windings I3 on the propelling units A and B are connected between the common return line I and the line II.

The sander control valve indicated by the numeral I4 applied to its body controls two switchesa normally open switch whose contactor is indicated at I5, and a normally closed switch whose contactor is indicated at I6.

As will be made clear hereinafter, during timed sanding the contactor I5 is closed and the contactor I6 remains closed, whereas during sanding at will, the contactor I6 is opened as the contactor I5 is closed. The contactor I5 bridges a contact II connected with one terminal of the battery 6, and a contact I8 permanently connected with line II and with the contact I9 controlled by contactor I 3. The other contact 2i controlled by contactor I6 is connected with line 9. A manually operable switch 22 is interposed so that the line 9 may be permanently deenergized if desired. Normally the switch 22 will remain closed.

The actuating mechanism of the contactors I5 and I6 would desirably be of the quick make 55 and break type, but these mechanisms are so familiar that the complication involved in illustrating them is not considered to be warranted. Accordingly a diagrammatic showing has been adopted.

Thus in Figure 1 the contactor I5 is shown as mounted on and insulated from the piston rod 23 of a pressure motor whose cylinder is indicated at 24. The coil compression spring 25 biases the contactor I5 in a circuit breaking direction.

The rod 23 is connected to a piston 26 working in cylinder 24, the space below the piston being vented to atmosphere as shown, and the space above the piston 26 being connected by a pipe 2'! with the housing I4 of the sander control valve.

The contactor I6 is mounted on and insulated from a piston rod 28. The pressure motor cylinder is shown at 29, the biasing spring at 3i, and the piston at 32. This contactor is biased in a closing direction by the spring 3|. The

space below the piston 32 is vented to atmosphere and the space above the piston is connected with body I 4 of the sander control valve by the pipe 33.

Thus if the sander valve be operated to admit air to the pipe 2! alone, all the magnet valve windings I3 and I2 throughout the train will be energized, but if the sander valve admits air simultaneously to the pipes 21 and 33, only the windings I3 on the propelling units will be energized.

The magnet valves, of which the windings I2 and I3 are components, are identical. One such unit having a winding I3 is illustrated in Figure 2. In this figure the lines I and II are illustrated as connected to opposite terminals of the winding I3. Upon energization of the winding I3, an armature 34 is forced downward against the thrust of acoil compression spring 35 in the valve body 36. This unseats the supply valve 31 and seats the vent or exhaust valve 38, the effect being to admit air under pressure from the main reservoir pipe M which is connected to a main reservoir 39 and extends throughout the train.

If it is not desired to run a main reservoir pipe throughout the train, any other source of compressed air on the various vehicles may be used, such as the supply reservoirs characteristic of Schedule HSC. The particular source of air is immaterial to the invention and not a patentable feature thereof.

Thus, when the winding I3 is energized, air under pressure from any suitable source is admitted by way of pipe 42 to the space above the piston 43, forcing the piston 43 downward in its cylinder 44, against the resistance of the coil compression spring 45. This unseats a local sanding valve 46 and admits air from the same source to the sander pipes 48. These lead to sanding units conventionally indicated at 49. These units may be of any known type, adapted to be rendered active by the admission of air under pres sure thereto. In fact, the details of the mechanisms controlled by the magnet valves are not {material and any sanding device capable of magnetic control may be substituted.

From what has been explained so far, it is apparent that in timed sanding all the sanders will be operated if the switch 22 is closed, because all the windings I2 and I3 throughout the train would be energized. However, in sanding at will, the opening of the contactor I6 concurrently with the closing of the contactor I5 will cause energization of the windings I3 on the propelling units only, so that with sanding at will, sanding occurs only in front of the propelling wheels.

This scheme of selective energization of one or both circuits forming part of a complete sander system is one of the major concepts of the present invention and may be produced by various specifically different means.

The particular sanding valve shown in Figures 1 and 3 to 5 inclusive, is the preferred controller, and offers the added advantage of simple means for terminating timed sandimr.

The main reservoir, shown at 39, can be considered as virtually an unlimited source of air at approximately constant pressure. The timing reservoir 5| is a small reservoir or volume chamber which is charged under running conditions, and furnishes the air to operate the switch I5 during timed sanding. The duration of operation is limited by dissipation of pressure in the 1 body I.

reservoir 5| caused by flow through a timing choke 52. During sanding at will, the switches |5 and iii are operated simultaneously by air drawn directly from the main reservoir 39, and not from timing reservoir 5|.

The main reservoir 39 is connected by a pipe to the main reservoir port 53 in'body. M of thesanding control valve. The timing reservoir 5| is connected by a pipe to the timing port 54 in the The pipe 21 is connected to a port 55 in body M, which is shown in free communication with the choke 52. The port 56 is an atmospheric.

-- pressure at the commencement of an emergency application.

Many such mechanisms are known in the air rake art, and since their particular construc-' port 56, so that this port is constantly open to atmosphere. It should also be observed that the port 53 leads around the bushing 6| and consequently is in constant communication with the port 62 which supplies air to the valve which coni I trols sanding at will. Hence this supply of air is not controlled by the balanced piston valve 63.

The valve 63 is shown as constructed of two interlocked parts, but to all intents and purposes in a single balanced piston valve of the inside cut-off type having a reduced middle portion 64. The valve is so dimensioned, that when the valve is in the normal position of Figure 3, the reduced portion connects the ports 53 and 54, establishing a charging path from the main reservoir to the timing reservoir. At the same time the valve blanks port 55, so that main reservoir air is cut off therefrom. Hence port 55 is then maintained at atmospheric. pressure by the atmospheric choke 52.

The valve 63 is held in its upper or normal position by a coil compression spring, 65 which reacts against the piston 65 fixed to the lower end of the valve 63. This piston works in a bushing 67 mounted in the lower end of the body l4,

and in the upper or normal postion (Figure 3) exposes bleed or vent ports 68 which lead from the space below the piston around. the piston and by Way of a small port 69 to thetiming choke 52.

Consequently, in the normal position of Figure 3, the space below piston 66 is vented to atmosphere, and the spring 65 alone holds the valve in its normal position.

Working in a cylinder bushing H pressed into the body M is a free piston l2. This piston abuts the upper end of the valve 53 and is, itself, engaged on its upper side by a push rod '53 which is guided for axial motion in a bushing l l mounted in the upper cap of the body 54.

The push rod 23 carries a hand button known as the timed sanding button. If this will.

held closed against an inserted seat bushing 18 by main reservoir pressure and by a coil compres-' emergency valve 58 operates to admit air under pressure through the port 51 to the space above the piston 52, the valve 63 will be forced downward far enough to expose port 16, thus subjecting piston 56 to timing reservoir pressure, whereupon the piston shifts the valve 63 full stroke downward to the position of Figure 1.

This movement causes the valve to blank'the main reservoir port 53 and connect the timing chamber port 54 with port 55. The effect is to establish a connection between the timing reser-v voir and the space above the holding piston 66 and also between the timing reservoir and pipe 27 and choke 52. Consequently timing reservoir pressure'retains the valve 63 in its lowermost po-.

sition' and contactor l5 closed until the bleed action oftiming choke 52 reduces timing reservoir pressure to a point at which the spring 65 can return the valve to normal position.

- By this time the emergency valve 58 may have reset,nbut whether it has or not, the bleed of pressure through the port 52 will ultimately cause the opening of the contactor I5, so that so far as an automatic emergency is concerned, sanding will terminate at the end of the time interval,

whether the valve 58 has reset or not.

Formed on the side of the body I4 is an enlargement which houses the valve for sanding at This is simply a poppet valve ll normally sion spring 79. The valve may be forced open by a button 8| known as the sanding at will button; This button operates a. stem which is ported as indicated at 82, the ports being such thatwhen the valve i1 is closed, the port 32 vents the passage 83. When the button 6| is forced in- WardQthis vent is closed, the valve T! is unseated, and main reservoir air flows by way of port 53 and port 52 past valve Ti to passage 83;

When this occurs the rising pressure in passage 83 is communicated to the pipe 33 connected therewith, so that piston 32 is forced downward and contactor I6 is opened. The efiect is to prevent energization of the sanding circuit on the trailers. Passage 83 leads to the space below the piston 66 and thence by way of the ports 68 and 69 to port and consequently to the space above piston 26 which moves down to shift contactor I5 and energize the sanding circuit on the propelling units. 6

In Figure 4 the parts are shown in the position which they assume in timed sanding. As already explained, the valve will not be restored automatically to the normal position of Figure 3 until pressure above the piston 66 has been bled away through the choke 52. If the engineer wishes to terminate timed sanding, caused, let

us-say, by depression of the button 15, he presses the button 8|. This admits main reservoir air to the port 83 and develops main reservoir pressure beneath the piston 66. The effect is to force this piston up and restore valve 63 to the normal position of Figure 3. This reconnects the main reservoir with the timing reservoir, blanks the port 55 so that the pipe 21 will be vented quickly through the choke 52, and blanks the port 16 so that the development of retaining pressure above the pistong66 is inhibited. Figure 5 shows the positions of the parts during this restoring opration. Y

To recapitulate, the depression of button 15 will initiate timed sanding which will occur in front of all braked wheels. This will continue buttonbe forced down by the operator, or if the" for the time interval determined by the reservoir 5| and the choke 52, but can be terminated at any time by pressing the button 8| and holding it until the valve resets, as it will do very 5' quickly.

Sanding at will may be caused at any time by pressing the button BI and will occur only on the propelling units, because the operation of this button causes the closing of the switch [5 and the concurrent opening of the switch l6.

While the sanding valve illustrated in Figures 3, 4 and 5 develops its greatest utility in conjunction with the selective circuit scheme illustrated in Figure 1, it can be used for any purpose for which the sanding valve shown in my prior patent above identified is suited, and when so used, offers at least the advantage that timed sanding can be terminated by operating the sanding at will button.

20' While one embodiment of the invention has been described in detail, various changes are possible within the scope of the invention, and the detailed disclosure above made should be interpreted as illustrative and not limited.

What is claimed is:

1. In a train sanding system, the combination of sanders arranged to sand braked wheels throughout the train, some only of said wheels being propelling wheels; and a single controlling means biased to a non-sanding position and capable selectively of two distinct single manipulations, one such manipulation operating the controller to cause all the sanders to operate and .the other manipulation operating the controller to cause only the sanders for propelling wheels to operate.

2. In a train sanding system, the combination of sanders arranged to sand braked wheels throughout the train, some only of said wheels 40 being propelling wheels; electrically controlled means for putting said sanders into and out of operation; circuits including said electrically controlled means, said circuits being normally conditioned to suspend sanding, there being one 45 circuit for the electrically controlled means of sanders which sand propelling wheels and another circuit for the electrically controlled means of the remaining sanders; and a controlling switching mechanism capable selectively of two 50 distinct single manipulations one of which conditions the first circuit alone to cause sanding and the other of which conditions both circuits to cause sanding.

3. In a train sanding system, the combina- 55 tion of sanders arranged to sand braked wheels throughout the train, some only of said wheels being propelling wheels; a single controlling means biased to a non-sanding position and capable selectively of two distinct single manipu- 60 lations, one such manipulation operating the controller to cause all the sanders to operate and the other manipulation operating the controller to cause only the sanders for propelling wheels to operate; and timing means arranged to be 65 put into action by the first recited manipulation, and serving to control said controlling means to delay termination of sanding thereby, whereby continuous sanding for a timed period is secured.

4. In a train sanding system, the combination of sanders arranged to sand braked wheels throughout the train, some only of said wheels being propelling wheels; a single controlling means biased to a non-sanding position and ca- 75 pable selectively of two distinct single manipulations, one such manipulation operating the controller to cause all the sanders to operate and the other manipulation operating the controller to cause only the sanders for propelling wheels to operate; timing means arranged to be put into action by the first recited manipulation, and serving to control said controlling means to delay termination of sanding thereby, whereby continuous sanding for a timed period is secured; and means operable at will to arrest the action of said timing means and thus expedite termination of sanding.

5. In a train sanding system the combination of sanders arranged to sand wheels throughout the train, some only of said wheels being propelling wheels; electrically controlled means for putting said sanders into and out of operation; circuits including said electrically controlled means; selective switching means controlling said circuits, said switching means being capable of two manipulations, in the first of which the control means of all the sanders are operated and in the second of which only the control means for sanders for propelling wheels are operated; and timing means for establishing a defi nite duration of sanding arranged to be rendered active only by the first manipulation to cause sanding to continue for a definite time period and arranged to be put out of action before the termination of said period by the second manipulation.

6. In a controlling valve for sanders, the combination of a source of operating air; a pressure operated device which when subjected to pressure causes sanding; two controlling means each operable to subject said device to pressure; means for restoring each of said controlling means to inactive condition; timing means serving to delay such restoration of one of said controlling means; and resetting means for said timing means arranged to be operated by the operation of other controlling means.

7. In a controlling device for sander mechanisms, the combination of a source of air under pressure; a device which when subject to pressure causes sanding; manually operable valve means for admitting pressure fluid from said source to said device at will; a second manually operable valve means for admitting pressure fluid from said source to said device; timing means rendered active upon the operation of said second valve means and serving upon the actuation thereof to hold said valve means open for a definite period and then cause it to close; and means rendered effective by operation of the first valve means to cause the second valve means to close irrespective of the action of said timing means.

8. The combination of a normally inactive sander, a fiuid pressure motor having a restricted vent and arranged to cause operation of said sander when said motor is subjected to pressure; a manually operable admission valve for admitting motive fluid to said motor at a rate exceeding the capacity of said vent; yielding means for closing said admission valve; a second manually operable admission valve for admitting motive fluid to said motor at a rate exceeding the capacity of said vent; yielding means urging said second valve in a closing direction; means associated with the first admission valve and effective in the open position thereof to delay closure therefor for a definite time period; and means associated with the second admission valve and effective in the open position thereof to force the first admission valve closed irrespective of the action of said delay means.

9. The combination of a source of fluid under pressure; at least one normally closed sander valve; a sanding motor serving upon the admission of pressure fluid thereto to cause opening of said sander valve; a timing reservoir; a doubleacting expansible chamber motor having a reversely shiftable abutment; a timing valve arranged to shift with said abutment, said timing valve having a normal position in which it ectablishes a charging connection from said source to said reservoir, and an abnormal position in which it closes said connection, connects said reservoir with both of said motors and vents pressure fluid slowly therefrom, the connections being such that the abutment of the double acting motor is then urged by pressure in the timing reservoir in a direction to hold said timing valve in abnormal position; yielding means urging the timing valve toward normal position; means for shifting the timing Valve to abnormal position; an admission and exhaust valve mechanism including means biasing the same to its exhaust position, said mechanism being so arranged that it controls pressure acting in said abutment in a direction to urge the timing valve toward normal position; and means eifective in the normal position of the timing valve to subject said sanding motor to pressure control by said admission and exhaust valve.

10. The combination of a source of fluid pressure; a sanding motor serving upon the admission of pressure fluid thereto to supply energy to cause sanding; a timing reservoir; a doubleacting expansible chamber motor having a reversely shiftable abutment; a timing valve arranged to shift with said abutment, said timing valve having a normal position in which it establishes a charging connection from said source to said reservoir and an abnormal position in which it closes said connection, connects said reservoir with both said motors and vents pressure fluid slowly therefrom, the connection being such that the abutment of the double-acting motor is then urged by pressure inthe timing reservoir in a direction to hold said timing valve in abnormal position; an admission and exhaust valve mechanism including means biasing the same to its exhaust position; said mechanism being arranged to control pressure acting on said abutment in a direction to urge the timing valve toward normal position; means effective in the normal position of the timing valve to subject said sanding motor to pressure control by said admission and exhaust valve; a plurality of sanders arranged to be energized simultaneously by the admission of pressure to said sanding motor; a pressure operated motor rendered effective by the admission of pressure fluid thereto to inhibit the energization of a part of said sanders; and connections whereby the pressure in the last named motor is controlled by said admission and exhaust valve.

CHARLES A. CAMPBELL. 

